The present application relates to an infusion state detection system configured to detect an abnormality in an infusion state when a liquid such as a medicinal solution is delivered using an infusion line.
The infusion line is formed by connecting an infusion set such as a medical bag, a tube, and an indwelling needle, for treatment of continuously administering a medicinal solution to a patient with an arbitrary supply amount. This type of treatment demands ensured conduction in the infusion line and stable delivery of the medicinal solution. Generally, an infusion pump includes a pressure sensor for detecting the pressure in the infusion line and an abnormality (occurrence of occlusion) of a conduction state in the infusion line is detected on the basis of a pressure value detected by the sensor.
Meanwhile, potential adverse events during infusion include an extravasation, that is, leakage of the medicinal solution into the subcutaneous tissue between the blood vessel and the epidermis as a result of a dislocated indwelling needle of the infusion line from the blood vessel into which the needle is inserted. In this case, even though the pressure inside the infusion line increases because the medicinal solution is pushed into the subcutaneous tissue, this degree of increase is smaller than a case where the infusion line is completely occluded, and thus, it is difficult to detect the increase with a sensor attached to the infusion pump in many cases. Moreover, there may be a case where the pressure increase due to extravasation is substantially equal to the degree of a pressure change induced by a posture change (standing up, etc.) of the patient, venous pressure fluctuation, or the like. Therefore, it difficult to determine the infusion state merely by monitoring the pressure in the infusion line during infusion. This leads to an unfavorable case, in the infusion state detection system, where reliability of detection is lowered due to an occurrence of misreporting, overlooking of the extravasation, or the like.
As a technique for solving these problems, a system disclosed in JP 3551974 B changes the flow rate of the medicinal solution during infusion and detects a pressure change accompanying the flow rate change, thereby distinguishing the liquid delivery resistance of the infusion line and the pressure change due to other factors so as to grasp the infusion state.